The present invention relates to pyrazoloacridone derivatives having anti-tumor activity.
As a pyrazoloacridone derivative, 6H-pyrazolo[4,5,1-d,e]acridin-6-one, which is the compound of the formula (I) mentioned below wherein R.sup.1, R.sup.2 and R.sup.3 are hydrogen atoms, is known [Ann. Chem., 677, 157 (1964)]. However, pyrazoloacridone derivatives having anti-tumor activity have not been known.
As tetracyclic heterocyclic compounds having anti-tumor activity, anthra[1,9-c,d]pyrazol-6(2H)-one derivatives wherein anthraquinone and pyrazole ring are peri-fused are disclosed in Japanese Published Unexamined Patent Application No. 51268/82 (U.S. Pat. No. 4,556,654).